The purpose of this research is to estimate the ranges of risks of cancer from exposure to exogenous estrogens among women, and among male and female children of women exposed to these substances in several sets of circumstances. The general method will be to identify cohorts of exposed persons and otherwise comparable non-exposed persons and to identify their total cancer experience through the Connecticut Tumor Registry. Particular attention will be paid to reproductive system cancers. Each cohort will be managed as a special subset of the Registry, using study and follow-up methods normally conducted by the Registry. The establishment and follow-up of each specially defined subset will be an extension of current Registry activities. These cohorts will include: a retrospective-prospective set of mothers and their offspring exposed during the mothers' pregnancies; an overlapping cohort of persons with known inrauterine exposure and current known physical examination status to be followed for development and/or progression of precancerous conditions, particularly vaginal adenosis. The feasibility will be explored of establishing a cohort of women treated with exogenous estrogens for gynecological problems. The cohorts will be limited at this time to persons identified within the first 3 years, but follow-up capabilities of the Connecticut Tumor Registry will permit periodic determination of cancer rates among case and control groups thereafter. In addition, the descriptive epidemiology of cancer in children and adolescents in Connecticut will be brought up to date and presented as a background for cohort studies and to identify possible related cancer risks that have not otherwise been identified. If results of preliminary work indicate need for expansion of the cohorts and/or additional studies, they will be recommended, but the design should yield usable data within limits defined in the application.